Why is (n-1)(n+1)=n^2-1?
12.06.2025 01:36

n^2 - n + n - 1
xxx x
If you cut off the end of that rectangle, you make it smaller, 2 * 3 and a separate nub of size 1 * 2
Will friendly dogs protect their owners?
And you are left with almost a square. One less than the square of side n.
xxxx
xxx
Are you worried that the 2024 US presidential election will result in a close race?
xxx x
The more direct answer is to look at a rectangle with sides of n + 1 and n - 1, let’s go with n = 2
n^2 - 1
Mariners fall flat again: 'We'll keep fighting' - The Seattle Times
So, that’s a rectangle with sides 2 and 4.
xxxx
xx
Trump proclamation seeks to restrict international students from Harvard - The Washington Post
Move the nub up to the top:
The basic answer is that you cross-multiply the values in each factor:
(n - 1)(n + 1)
Genetic and biological clues point to inflammation’s role in mental health - PsyPost
xxx